mesa/format_utils: Prefix and expose the conversion helper functions

Signed-off-by: Jason Ekstrand <jason.ekstrand@intel.com>

v2 by Samuel Iglesias <siglesias@igalia.com>:
- Fix compilation errors

Signed-off-by: Samuel Iglesias Gonsalvez <siglesias@igalia.com>
Reviewed-by: Ian Romanick <ian.d.romanick@intel.com>
Reviewed-by: Jason Ekstrand <jason.ekstrand@intel.com>

1 files changed, 105 insertions, 0 deletions

diff --git a/src/mesa/main/format_utils.h b/src/mesa/main/format_utils.h
index 9f778e3..df53edf 100644
--- a/src/mesa/main/format_utils.h
+++ b/src/mesa/main/format_utils.h
@@ -33,6 +33,111 @@
 
 #include "imports.h"
 
+/* Only guaranteed to work for BITS <= 32 */
+#define MAX_UINT(BITS) ((BITS) == 32 ? UINT32_MAX : ((1u << (BITS)) - 1))
+#define MAX_INT(BITS) ((int)MAX_UINT((BITS) - 1))
+
+/* Extends an integer of size SRC_BITS to one of size DST_BITS linearly */
+#define EXTEND_NORMALIZED_INT(X, SRC_BITS, DST_BITS) \
+      (((X) * (int)(MAX_UINT(DST_BITS) / MAX_UINT(SRC_BITS))) + \
+       ((DST_BITS % SRC_BITS) ? ((X) >> (SRC_BITS - DST_BITS % SRC_BITS)) : 0))
+
+static inline float
+_mesa_unorm_to_float(unsigned x, unsigned src_bits)
+{
+   return x * (1.0f / (float)MAX_UINT(src_bits));
+}
+
+static inline float
+_mesa_snorm_to_float(int x, unsigned src_bits)
+{
+   if (x <= -MAX_INT(src_bits))
+      return -1.0f;
+   else
+      return x * (1.0f / (float)MAX_INT(src_bits));
+}
+
+static inline uint16_t
+_mesa_unorm_to_half(unsigned x, unsigned src_bits)
+{
+   return _mesa_float_to_half(_mesa_unorm_to_float(x, src_bits));
+}
+
+static inline uint16_t
+_mesa_snorm_to_half(int x, unsigned src_bits)
+{
+   return _mesa_float_to_half(_mesa_snorm_to_float(x, src_bits));
+}
+
+static inline unsigned
+_mesa_float_to_unorm(float x, unsigned dst_bits)
+{
+   if (x < 0.0f)
+      return 0;
+   else if (x > 1.0f)
+      return MAX_UINT(dst_bits);
+   else
+      return F_TO_I(x * MAX_UINT(dst_bits));
+}
+
+static inline unsigned
+_mesa_half_to_unorm(uint16_t x, unsigned dst_bits)
+{
+   return _mesa_float_to_unorm(_mesa_half_to_float(x), dst_bits);
+}
+
+static inline unsigned
+_mesa_unorm_to_unorm(unsigned x, unsigned src_bits, unsigned dst_bits)
+{
+   if (src_bits < dst_bits)
+      return EXTEND_NORMALIZED_INT(x, src_bits, dst_bits);
+   else
+      return x >> (src_bits - dst_bits);
+}
+
+static inline unsigned
+_mesa_snorm_to_unorm(int x, unsigned src_bits, unsigned dst_bits)
+{
+   if (x < 0)
+      return 0;
+   else
+      return _mesa_unorm_to_unorm(x, src_bits - 1, dst_bits);
+}
+
+static inline int
+_mesa_float_to_snorm(float x, unsigned dst_bits)
+{
+   if (x < -1.0f)
+      return -MAX_INT(dst_bits);
+   else if (x > 1.0f)
+      return MAX_INT(dst_bits);
+   else
+      return F_TO_I(x * MAX_INT(dst_bits));
+}
+
+static inline int
+_mesa_half_to_snorm(uint16_t x, unsigned dst_bits)
+{
+   return _mesa_float_to_snorm(_mesa_half_to_float(x), dst_bits);
+}
+
+static inline int
+_mesa_unorm_to_snorm(unsigned x, unsigned src_bits, unsigned dst_bits)
+{
+   return _mesa_unorm_to_unorm(x, src_bits, dst_bits - 1);
+}
+
+static inline int
+_mesa_snorm_to_snorm(int x, unsigned src_bits, unsigned dst_bits)
+{
+   if (x < -MAX_INT(src_bits))
+      return -MAX_INT(dst_bits);
+   else if (src_bits < dst_bits)
+      return EXTEND_NORMALIZED_INT(x, src_bits - 1, dst_bits - 1);
+   else
+      return x >> (src_bits - dst_bits);
+}
+
 bool
 _mesa_format_to_array(mesa_format, GLenum *type, int *num_components,
                       uint8_t swizzle[4], bool *normalized);